Energy Transfer Across the Lumbosacral and Lower-Extremity Joints in Patients With Low Back Pain During Sit-to-Stand

The total normalized power flow pattern of the pelvis, thigh, and leg segments of asymptomatic and subjects with LBP.

The normalized segmental power flow pattern of the (A) pelvis, (B) thigh, and (C) leg segments of asymptomatic subject.

The normalized segmental power flow pattern of the (A) pelvis, (B) thigh, and (C) leg segments of asymptomatic subject.

Diagrams showing load and power flow analysis with the thigh segment as an example. (A) Load analysis. M and F are the moments and forces acting at the hip (proximal) and knee (distal) of the thigh segment and ω and v the angular and linear velocities of the segments. The subscript p and d represent proximal and distal, respectively. (B) Power flow at the proximal () and distal ends () of a body segment. Passive and active power flow are also shown.